A solid oxide electrochemical cell has sufficient reaction speed even without the use of an expensive precious metal catalyst because the electrochemical cell has high operation temperature (600 to 1000° C.). For this reason, a solid oxide electrochemical cell, when being used for a solid oxide fuel cell (SOFC), has the highest power generation efficiency as compared with the other types of fuel cells and generates little CO2, thereby being expected as a next-generation clean power generation system. When a solid oxide electrochemical cell is used for a high-temperature water vapor electrolyzer cell (SOEC), hydrogen can be fabricated at low applied voltage in principle because of the high operation temperature. Accordingly, a solid oxide electrochemical cell is expected also as a high-efficiency hydrogen manufacturing device.
A perovskite type oxide with high conductivity is generally used for an anode of this solid oxide electrochemical cell. The high-temperature operation type often employs a lanthanum-manganese based oxide (LaMnO3 based) for the anode. A middle-to-low-temperature operation type often employs a lanthanum-cobalt based oxide (LaCoO3 based) for the anode. The lanthanum-cobalt based oxide has high catalyst activity, and has high reactivity with a zirconia based oxide (ZrO2) which is generally used for an electrolyte. When these react with each other, a high-resistive phase such as La2Zr2O7 is formed, which results in a problem of deterioration in cell performance.